Polycarbonates are tough, clear, and highly impact resistant thermoplastic resins. Polycarbonates have excellent properties for applications such as baby bottles and water bottles. Residual monomer, such as Bisphenol A (BPA), may leach out of the polycarbonate at certain temperatures and expose the consumer to the residual BPA. The residual BPA may disrupt the endocrine system of various mammalian species, including humans.
There are known methods of adding diacid residues into polycarbonate that concern altering the physical properties of the resulting polycarbonate, but not removal of residual BPA.
U.S. Pat. No. 6,747,119 discloses a method for preparing a polycarbonate by adding a free hydroxyl-containing polycarbonate to a mixture of an optionally substituted aromatic dihydroxy diacid and a symmetrically optionally activated aromatic carbonic acid diester.
U.S. Pat. No. 6,307,005 discloses a method of preparing a polyestercarbonate using an interfacial polymerization reaction using a diacid.